MAGNETIC ENTROPY AND MAGNETIC HEAT CAPACITY NEAR THE FIRST-ORDER FERROMAGNETIC TO PARAMAGNETIC PHASE TRANSITION
Keywords:
ferromagnetic, paramagnetic, entropy, heat capacity, phase transitionAbstract
The continuous development of magnetization below the transition point is the characterization of the second order ferromagnetic (FM) phase to paramagnetic (PM) phase transition (FM-PM). The discontinuous change in magnetization along the hysteresis path is the characterization of the first order FM-PM phase transition. The manganites with the highest FM-PM transition temperature undergo a conventional second order phase transition, whereas for the lower FM-PM transition temperature manganites, the FM-PM phase transition is first order. In the presence of an external magnetic field, the first order FM-PM transition shifts towards the higher temperature while the width of thermal hysteresis in magnetization decreases gradually and the transition becomes second-order. The magnetic entropy and magnetic heat capacity near the first-order ferromagnetic to paramagnetic phase transition are discussed using Landau theory. The magnetic entropy and magnetic heat capacity are calculated near the phase transition. The theoretical results are discussed by piloting figures. We show that negative values of the magnetic entropy and positive values of magnetic heat capacity in the ferromagnetic phase increase with the increase of the magnetic field.
References
Alexandrov, A.S., Bratkovsky, A.M. (1999): Carrier density collapse and colossal magnetoresistance in doped manganites. – Physical Review Letters 82(1): 141-143.
Amaral, V.S., Araújo, J.P., Pogorelov, Y.G., Sousa, J.B., Tavares, P.B., Vieira, J.M., Algarabel, P.A., Ibarra, M.R. (2003): Tricritical points in La-based ferromagnetic manganites. – Journal of Applied Physics 93(10): 7646-7648.
Belevtsev, B.I., Zvyagina, G.A., Zhekov, K.R., Kolobov, I.G., Beliayev, E.Y., Panfilov, A.S., Galtsov, N.N., Prokhvatilov, A.I., Fink-Finowicki, J. (2006): Influence of magnetic field on the paramagnetic-ferromagnetic transition in a La 1− x Ca x Mn O 3 (x≈ 0.25) crystal: Ultrasonic and transport studies. – Physical Review B 74(5): 11p.
Bishwas, M.S., Poddar, P. (2016): Study of magnetic entropy and heat capacity in ferrimagnetic Fe3Se4 nanorods. – Journal of Physics D: Applied Physics 49(19): 6p.
Das, A.N., Ghosh, B. (1983): Effect of pressure on the thermal hysteresis of a first-order transition. – Journal of Physics C: Solid State Physics 16(10): 1799-1802.
Ghosh, K., Lobb, C.J., Greene, R.L., Karabashev, S.G., Shulyatev, D.A., Arsenov, A.A., Mukovskii, Y. (1998): Critical phenomena in the double-exchange ferromagnet La 0.7 Sr 0.3 MnO 3. – Physical Review Letters 81(21): 4740-4743.
Imry, Y., Wortis, M. (1979): Influence of quenched impurities on first-order phase transitions. – Physical Review B 19(7): 6p.
Kapusta, O., Zeleňáková, A., Hrubovčák, P., Tarasenko, R., Zeleňák, V. (2018): The study of entropy change and magnetocaloric response in magnetic nanoparticles via heat capacity measurements. – International Journal of Refrigeration 86: 107-112.
Kim, D., Revaz, B., Zink, B.L., Hellman, F., Rhyne, J.J., Mitchell, J.F. (2002): Tricritical Point and the Doping Dependence of the Order of the Ferromagnetic Phase Transition of L a 1− x C a x M n O 3. – Physical Review Letters 89(22): 14p.
Mukherjee, P.K., Sarkar, P., Chattopadhyay, A.K. (2018): Role of external and internal perturbations on ferromagnetic phase transitions in manganites: existence of tricritical points. – Journal of Physics: Condensed Matter 30(29): 16p.
Mydeen, K., Sarkar, P., Mandal, P., Murugeswari, A., Jin, C.Q., Arumugam, S. (2008): Hydrostatic pressure effect on archetypal Sm 0.52 Sr 0.48 Mn O 3 single crystal. – Applied Physics Letters 92(18): 4p.
Palacios, E., Bartolomé, J., Wang, G., Burriel, R., Skokov, K., Taskaev, S., Khovaylo, V. (2015): Analysis of the magnetocaloric effect in Heusler alloys: study of Ni50CoMn36Sn13 by calorimetric techniques. – Entropy 17(3): 1236-1252.
Sarkar, P., Arumugam, S., Mandal, P., Murugeswari, A., Thiyagarajan, R., Muthu, S.E., Radheep, D.M., Ganguli, C., Matsubayshi, K., Uwatoko, Y. (2009a): Pressure induced critical behavior of ferromagnetic phase transition in Sm-Nd-Sr manganites. – Physical Review Letters 103(5): 4p.
Sarkar, P., Mandal, P., Mydeen, K., Bera, A.K., Yusuf, S.M., Arumugam, S., Jin, C.Q., Ishida, T., Noguchi, S. (2009b): Role of external and internal perturbations on the ferromagnetic phase transition in Sm 0.52 Sr 0.48 MnO 3. – Physical Review B 79(14): 6p.
Sarkar, P., Mandal, P., Bera, A.K., Yusuf, S.M., Chandra, L.S., Ganesan, V. (2008): Field-induced first-order to second-order magnetic phase transition in Sm 0.52 Sr 0.48 MnO 3. – Physical Review B 78(1): 4p.
Takahashi, Y., Nakano, H. (2004): Temperature and magnetic field dependence of the heat capacity in itinerant electron ferromagnets. – Journal of Physics: Condensed Matter 16(25): 4505-4520.
Tomioka, Y., Kumai, R., Ito, T., Tokura, Y. (2009): Magnetic and electronic properties of Eu 1− x Sr x MnO 3 (0.3< x< 0.7) single crystals. – Physical Review B 80(17): 8p.
van Dijk, N.H. (2021): Landau model evaluation of the magnetic entropy change in magnetocaloric materials. – Journal of Magnetism and Magnetic Materials 529: 10p.
